Oh, and I guess this should be mentioned as well student.... depending on where you are located, you may not have enough wind for your project.... unless you go 100 feet or more in the air. I would hate to see you go through all this time and trouble to find you cannot charge your battery because your wind generator does not spin. I forget the website, but there is a site that gives you the average wind measurements in your area. You will want to find this site and see if you have enough wind there. I doubt you will have the money, time, experience, and OK from your school to set up a 150 foot tower, even if it is just a pole with guide wires. You have to understand the physics involved with such a tower. the wind will be forcing your wind generator to the side putting and extreme amount of force on your tower. We are talking several hundreds of pounds of pressure (if not thousands). The higher the tower, the more stress that your tower will be under. This could be dangerous stuff if you do not do it right.
You may want to look into solar as a substitute or possibly a combination of the two. If you have a stream (especially one that is comming off of a hill) you may want to think about a hydro generator..... they produce 24/7, and if you build pressure by bringing water from a higher elevation down to a lower one with pipes (that also decrease in size a bit as you get lower), you can produce a really good amount of power. You can get them spinning very well and even gear them up to get induction motors to spin even faster, which is a good thing.
You could make a project out of the solar panels as well. You can buy several single cells and make your own solar panel (saves money and shows you have some skills for your teacher to see that he can still grade you on instead of the wind generator).
And, after you are all through with this, do not forget you will need a charge controller and possibly a charge dump. When your battery is full, you need something there to stop the batteries from overcharging so you still have a greenhouse left so your teacher can give you students lighting projects to do .
Devon